eventfd_ctx...e_wait_queue(9)

🎀 eventfd_ctx_remove_wait_queue — Kernel API Manual ✨

okay so bestie, welcome to the Kernel API Manual, and today's main character is eventfd_ctx_remove_wait_queue — yes the title is truncated in the header (eventfd_ctx...e_wait_queue(9), we don't know her full name, she's mysterious like that 💅).

---

🌸 NAME 🌸

eventfd_ctx_remove_wait_queue — read the current counter and removes wait queue. two things, one function, she's multitasking, we stan 🫶

---

⭐ SYNOPSIS ⭐

int eventfd_ctx_remove_wait_queue (struct eventfd_ctx *ctx ,
wait_queue_entry_t *wait , __u64 *cnt );

literally just three args, no cap. look at her go 🦋

---

💖 ARGUMENTS 💖

• ctx — [in] Pointer to eventfd context. yes it's in, meaning you're feeding it in, you're the giver here 🎁
• wait — [in] Wait queue to be removed. this is the entry getting yeeted out of the queue, byeee 😭
• cnt — [out] Pointer to the 64-bit counter value. this one's out — the function writes the 64-bit counter value back to you through this pointer. she's giving, you're receiving 💫

---

🔥 DESCRIPTION 🔥

Returns 0 if successful, or the following error codes:

• -EAGAIN : The operation would have blocked.

lowkey important: -EAGAIN here means the operation would have blocked — that's the whole mood of that error code, don't forget it 🙈

This is used to atomically remove a wait queue entry from the eventfd wait queue head, and read/reset the counter value. like, all of it, in one atomic little motion — no half-steps, no race conditions, no drama. the way she does remove + read + reset as one unit?? iconic 👑

---

🦋 SEE ALSO 🦋

Kernel file ./fs/eventfd.c — go read the source bestie, it's all in there 🌈

• eventfd_signal_mask(9)
• eventfd_ctx_put(9)
• eventfd_fget(9)
• eventfd_ctx_fdget(9)
• eventfd_ctx_fileget(9)

the whole friend group honestly, they all hang out in ./fs 🍓

---

and that's the page, bestie!! 💜 this one's from ./fs, dated October 2026, and it's filed under eventfd_ctx...e_wait_queue(9) — same truncated queen energy in the footer as in the header, she's consistent, periodt. go forth and remove those wait queue entries atomically ✨🧚